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M. Alonzi et al. / Journal of Catalysis 309 (2014) 260–267
2.2. Preparation of PS-Cl 1a–c
(35 mL) and dichloromethane (35 mL). The collected polymer
beads were then vacuum dried overnight at room temperature.
The degree of functionalization was determined to be 2.54 mmol
TBD/g by elemental analysis: C 68.45, H 7.46, N 10.67 (yield 87%,
0.35 g).
2.2.1. PS-Cl 1a
A reaction vessel immersed in an oil bath, equipped with con-
denser, mechanical stirrer and nitrogen inlet/outlet was charged
with water (80 mL), polyvinylalcohol (MW 85,000–124,000, 99%
hydrolyzed) (0.08 g), and NaCl (2.65 g) and stirred for 24 h at room
temperature. A mixture of 4-vinylbenzylchloride (13), (1.6 mL),
divinylbenzene (14) (0.4 mL), 2-ethylhexanoic acid (EEA, 2 mL)
and AIBN (0.02 g, 1% w/w monomers) was then added into the
reactor. The system was kept under stirring and purged with nitro-
gen for 30 min. Then, the reaction was warmed up to 85 °C under
mechanical stirring. After 24 h, the reaction was allowed to reach
room temperature and the polymer beads were filtered. The prod-
uct was washed in a Soxhlet extractor for 24 h with water, THF and
hexanes and vacuum dried overnight (yield 70%, 1.41 g).
2.4. Procedure for Michael reaction between 4-hydroxycoumarine (4)
and a,b-unsaturated ketones 5–8
2.4.1. Preparation of 4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-
chromen-2-one (Warfarin, 9)
In a screw-capped vial equipped with a magnetic stirrer,
4-hydroxycoumarine (4) (0.146 g, 0.9 mmol), (3E)-4-phenyl-but-
3-en-2-one (5) (0.131 g, 0.9 mmol), catalyst 3c(0.05 eq) and cyclo-
pentyl methyl ether (0.5 mL) were consecutively added and the
mixture was stirred at 100 °C. After 96 h, the catalyst was recov-
ered by filtration, washed with 2-Me-THF (5 mL) and vacuum dried
overnight. The organic solvent was evaporated under reduced
pressure to give crude 4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-
chromen-2-one (9) as a white solid. (0.266 g, 96% yield). 1H NMR
(CDCl3, 400 MHz): 1.68, s, 3H; 1.72, s, 3H; 2.07, t , 2H, J = 6 Hz;
2.46, s, 3H; 2.47–2.57, m, 2H; 3.19, s, 1H; 3.31, d, 2H; J = 21 Hz;
3.86, dd, 2H; J1 = 20 Hz, J2 = 8 Hz; 4.14–4.19, m , 1H; 4.27–4.31,
m, 1H; 4.70, d, 1H, J = 10 Hz; 7.21–7.37, m, 7 H; 7.49–4.59, m ,
1H. 13C NMR (CDCl3, 100.6 MHz): 27.7; 28.2; 34.1; 40.0; 42.5;
99.0; 100.4; 101.1; 104.2; 116.5; 116.6; 122.7; 123.0; 123.6;
123.9; 126.5; 126.9; 127.2; 128.6; 129.2; 131.5; 132.0; 141.4;
143.1; 153.0; 158.9; 159.8; 161.2; 162.1.
2.2.2. PS-Cl 1b
The reaction vessel was charged with water (80 mL), polyvinyl-
alcohol (MW 13,000–23,000, 89% hydrolyzed) (0.08 g), NaCl
(2.65 g) and stirred for 24 h at room temperature. A mixture of
4-vinylbenzylchloride (13) (1.6 mL), divinylbenzene (14) (0.4 mL),
1-chlorodecane (CD, 2 mL) and AIBN (0.02 g, 1% w/w monomers)
was added. The system was kept under stirring and purged with
nitrogen for 30 min. Then, the reaction was warmed up to 85 °C
under mechanical stirring. After 24 h, the reaction was allowed
to reach room temperature and the polymer beads were filtered.
The product was washed in a Soxhlet extractor for 24 h with water,
THF and hexanes and vacuum dried overnight (yield 72%, 1.45 g).
2.4.2. Preparation of 4-hydroxy-3-(1-(4-nitrophenyl)-3-oxobutyl)-2H-
chromen-2-one (Acenocoumarol, 10)
2.2.3. PS-Cl 6c
Prepared by following the procedure described above for 1a.
Porogen: Cyclohexanol (COX, 2 mL) (yield 65%, 1.31 g).
In a screw-capped vial equipped with a magnetic stirrer, 4-
hydroxycoumarine (4) (0.146 g, 0.9 mmol), (3E)-4-(4-nitro-
phenyl)-but-3-en-2-one (6) (0.172 g, 0.9 mmol), catalyst 3a
(0.05 eq) and cyclopentyl methyl ether (0.5 mL) were consecu-
tively added and the mixture was stirred at 100 °C. After 72 h,
the catalyst were recovered by filtration and washed with 2-Me-
THF (5 mL), and the solvent was evaporated under reduced pres-
sure to give crude 4-hydroxy-3-(1-(4-nitrophenyl)-3-oxobutyl)-
2H-chromen-2-one (10) as a brown solid; (0.300 g, 96% yield). 1H
NMR (CDCl3, 400 MHz): 1.73, s, 3H; 1.79, s, 3H; 1.93, m, 2H;
2.34, s, 3H; 2.39–2.52, m, 2H; 2.96, s, 1H; 3.24, s, 1H; 3.34, dd,
J1 = 20.3 Hz; J2 = 2.9 Hz, 2H; 3.90, dd, J1 = 20.5; J2 = 2.9 Hz, 2H;
3.90, dd, J1 = 20.5 Hz, J2 = 11 Hz, 2H; 4.27, m, 1H; 4.73, dd,
J1 = 12.6 Hz; J2 = 1.3 Hz, 1H; 7.25–7.44, m, 4H; 7.54, td, J1 = 7.7;
J2 = 1.3 Hz; 7.59, td, J1 = 7.7 Hz, J2 = 1.3 Hz, 1H; 7.82, dd,
J1 = 8.4 Hz, J2 = 1.3 Hz, 1H; 7.87, dd, J1 = 8.4 Hz, J2 = 1.3 Hz, 1H;
8.12–8.18, m, 2H. 13H NMR (CDCl3, 100 MHz): 26.5; 27.2; 35.2;
35.3; 41.9; 99.7; 100.9; 101.0; 102.5; 115.4; 115.6; 116.4; 116.5;
122.8; 122.9; 123.1; 123.6; 124.3; 128.8; 129.0: 132.3.
2.3. Preparation of catalysts 3a–c
2.3.1. Preparation of PS-TBD 3a
In a round-bottom flask equipped with a magnetic stirrer 1a
(0.4 g, 2.16 mmol), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) (2)
(4.45 g, 15 eq) and 3 mL of 1,4-dioxane were added. The reaction
was kept under stirring at 100 °C for 7 d. The polymer beads were
isolated by filtration and washed with THF (35 mL), chloroform
(35 mL) and dichloromethane (35 mL). The collected polymer
beads were then vacuum dried overnight at room temperature.
The degree of functionalization was determined to be 2.61 mmol
TBD/g by elemental analysis: C 68.67, H 14.29, N 10.95 (yield
85%, 0.34 g).
2.3.2. Preparation of PS-TBD 3b
In a round-bottom flask equipped with a magnetic stirrer 1b
(0.4 g, 2.16 mmol), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) (2)
(4.45 g, 10 eq) and 1.5 mL of 1,4-dioxane were added. The reaction
was kept under stirring at 100 °C for 7 d. The polymer beads were
isolated by filtration and washed with THF (35 mL), chloroform
(35 mL) and dichloromethane (35 mL). The collected polymer
beads were then vacuum dried overnight at room temperature.
The degree of functionalization was determined to be 2.51 mmol
TBD/g by elemental analysis: C 66.18, H 8.21, N 10.55 (yield 80%,
0.32 g).
2.4.3. Preparation of 4-hydroxy-3-(1-(4-chlorophenyl)-3-oxobutyl)-
2H-chromen-2-one (Coumachlor, 11)
In a screw-capped vial equipped with a magnetic stirrer, 4-
hydroxycoumarine (4) (0.146 g, 0.9 mmol), (3E)-4-(4-chloro-
phenyl)-but-3-en-2-one (7) (0.162 g, 0.9 mmol), catalyst 3b
(0.05 eq) and cyclopentyl methyl ether (0.5 mL) were consecu-
tively added and the mixture was stirred at 100 °C. After 96 h,
the catalyst were recovered by filtration and washed with 2-Me-
THF (5 mL), and the solvent was evaporated under reduced pres-
sure to give crude 4-hydroxy-3-(1-(4-chlorophenyl)-3-oxobutyl)-
2H-chromen-2-one (11) as a white solid (0.295 g, 96% yield); 1H
NMR (CDCl3, 400 MHz): 1.68, s, 3H; 1.72, s, 3H; 1.93, m, 2H;
2.36, s, 3H; 2.38–2.46, m, 2H; 3.23, s, 1H; 3.29, s, 1H; 3.57, s, 1H;
3.86, dd, 2H, J1 = 19.8 Hz, J2 = 2.4 Hz; 4.14–4.19, m, 1H; 4.64, dd,
1J, J1 = 11 Hz, J2 = 2.5 Hz; 7.13–7.34, m, 4H; 7.52, td, 1H,
2.3.3. Preparation of PS-TBD 3c
In a round-bottom flask equipped with a magnetic stirrer 1c (0.
4 g, 2.16 mmol), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) (2)
(6.1 g, 15 eq) and 5 mL of 1,4-dioxane were added. The reaction
was kept under stirring at 100 °C for 7 d. The polymer beads were
isolated by filtration and washed with THF (35 mL), chloroform